Treatment device for treating fluids, in particular liquid fluids, and treatment element of treatment device

ABSTRACT

A filter device for treating fluids, in particular for filtering fluids such as fuel, oil, or water, has a housing ( 56 ) with a housing pot ( 58 ), a housing cover ( 60 ), at least one inlet ( 88 ) for the fluid to be treated, and at least one outlet ( 82 ) for the treated fluid. A connecting head ( 12 ) has at least one feed ( 16 ) for the fluid to be treated and connectable to the at least one inlet ( 88 ), and/or at least one discharge ( 18 ). The connecting head ( 12 ) and the treatment element ( 14 ) can be connected to each other by means of a releasable bayonet-type connecting device ( 34 ) through the execution of a rotational/plug-in movement about a connecting axis ( 20 ) of the treatment device ( 10 ).

TECHNICAL FIELD

The invention relates to a treatment device, in particular a filterdevice for treating fluids, in particular for filtering fluids, inparticular liquid fluids, in particular fuel, oil, or water, inparticular of an internal combustion engine, in particular of a motorvehicle, the treatment device comprising a treatment element which has ahousing comprising a housing pot, a housing cover, at least one inletfor the fluid to be treated, and at least one outlet for the treatedfluid, as well as a connecting head having at least one feed for thefluid to be treated, said feed being connectable to the at least oneinlet, and/or at least one discharge for the treated fluid, saiddischarge being connectable to the at least one outlet, wherein theconnecting head and the treatment element can be connected to each otherby means of a releasable bayonet-type connecting device through theexecution of a rotational/plug-in movement about a connecting axis ofthe treatment device, and the connecting device has at least one housingconnecting part on the side of the housing and at least one headconnecting part on the side of the connecting head, said connectingparts being able to interact with each other in order to connect theconnecting device.

The invention also relates to a treatment element of a treatment device,in particular a filter device according to the invention for treatingfluids, in particular for filtering fluids, in particular liquid fluids,in particular fuel, oil, or water, in particular of an internalcombustion engine, in particular of a motor vehicle, the treatmentelement having a housing comprising a housing pot, a housing cover, atleast one inlet for the fluid to be treated, and at least one outlet forthe treated fluid, as well as a connecting head having at least one feedfor the fluid to be treated, said feed being connectable to the at leastone inlet, and/or at least one discharge for the treated fluid, whereinthe treatment element can be connected to a connecting head of thetreatment device by means of a releasable bayonet-type connecting devicethrough the execution of a rotational/plug-in movement about aconnecting axis of the treatment device, and the connecting device hasat least one housing connecting part on the side of the housing that caninteract with at least one head connecting part on the side of theconnecting head for the purpose of connecting the connecting device,wherein the at least one inlet can be connected to at least one feed ofthe connecting head for the fluid to be treated and/or the at least oneoutlet can be connected to at least one discharge of the connecting headfor the treated fluid.

BACKGROUND

DE 10 2010 035 465 A1 discloses a filter for filtering fluids, inparticular liquid fluids, in particular fuel or oil, in particular of aninternal combustion engine, the filter comprising a filter pot in whicha filter element is arranged, and a filter head having an inlet and/oran outlet for the fluid. The filter head and the filter pot areconnected to one another by means of a releasable bayonet-typerotational/plug-in connector. The rotational/plug-in connector comprisesat least two interacting catch components, one of which is connected tothe filter pot and the other of which is connected to the filter head.

The invention addresses the problem of providing a treatment device anda replaceable filter of a filter device of the aforementioned type, withwhich it is possible to facilitate the connection of the treatmentelement, in particular of the replaceable filter to the connecting headand facilitate separation from the connecting head. The invention isalso intended to reduce the space required, in particular for theconnecting device, in particular in the axial direction with respect tothe connecting axis.

SUMMARY

This problem is solved according to the invention in that: at least onefirst connecting part has a respective functional surface on faces lyingaxially opposite one another with respect to the connecting axis; atleast one second connecting part of the connecting parts has at leastone counter functional surface which engages behind one of thefunctional surfaces of the at least one first connecting part forinteraction purposes; at least one guiding element is arranged on theface of the at least one second connecting part, said guiding elementdelimiting at least one insert gap together with the at least onecounter functional surface, the axial extension of the insert gap withrespect to the connecting axis being at least as large as the maximumaxial distance between the two axially opposing functional surfaces ofthe at least one first connecting part; and the at least one firstconnecting part can be guided in the insert gap when the connectingdevice is being opened/closed, one of the functional surfaces of the atleast one first connecting part being guided along the counterfunctional surface, and the other functional surface being guided alongthe at least one guiding element.

Provided according to the invention is at least one guiding element, inparticular a guide peg, with the aid of which the at least one firstconnecting part can be guided on the side lying axially opposite to thecounter functional surface. The at least one connecting part can thus beguided between the at least one guiding element and the correspondingcounter functional surface of the at least one second connecting part.In this manner, a precise rotational/plug-in movement can be executed.It is furthermore possible to reduce the risk of the treatment elementbeing tilted relative to the connecting axis when beinginstalled/dismantled. With the aid of the at least one insert gap, theat least one first connecting part can be easily and accuratelypositioned relative to at least one second connecting part when thetreatment element is being installed.

The at least one counter functional surface engages behind at least oneof the functional surfaces of the at least one connecting part. In thismanner, between the at least one counter functional surface and thecorresponding functional surface, a tension connection can be realizedaxially to the connecting axis.

Advantageously for the realization of the bayonet-type connection, theat least one counter functional surface may extend circumferentiallywith respect to the connecting axis.

Advantageously, the circumferential extension of the regions of thebayonet-type connecting device in which the at least one counterfunctional surface interacts with the corresponding at least onefunctional surface in the closed state of the connecting device may beat least 50%, preferably more than 60% of the circumference of thetreatment element. In this manner, a corresponding larger region thatcan act in a force-transmitting manner can be realized. In addition, theforces between the treatment element and the connecting head can actcircumferentially better and more uniformly. It is also possible, then,to transmit greater forces overall. Thus, the stability of theconnection to the connecting device can be improved. The mechanical loadof the connecting device can thus be reduced. This can positively affectthe service life.

In an advantageous embodiment, the at least one counter functionalsurface and the at least one functional surface interacting therewithmay each comprise at least one latch element, in particular a latchingprojection or a latch section of at least one catch lock, which latchone behind the other or with or into one another in the closed positionof the at least one connecting device. The catch lock makes it possibleto reduce the risk of the connecting device being released through anundesired rotation of the treatment element about the connecting axis.In order to close and release the at least one catch lock, thecorresponding latch elements can be separated from one another or guidedpast one another by the corresponding rotation of the treatment element.So doing may require overcoming corresponding latching forces. Thepresence of the treatment element at the correct position thereof canalso be easily detected at such an increased expenditure of force in theinstallation.

In another advantageous embodiment, the connecting device may compriseat least one biasing element for realizing a mechanical bias with whichthe at least one counter functional surface can be pressed against theat least one functional surface. In this manner, the connecting devicecan be kept under a mechanical stress. Operational vibrations can thusbe dampened. It is also possible to reduce operational noise. Inparticular, any rattling that might occur can be prevented. Moreover, itis possible to generate or increase any latching force that must beovercome in order to close or open the latching.

The at least one biasing element may advantageously be arranged on theconnecting head. In this manner, the biasing element can be configuredas a lifetime component. The biasing element need not be replacedtogether with the treatment element.

Alternatively or additionally, at least one biasing element may bearranged on the housing. The biasing element then can be replacedtogether with the treatment element.

The at least one biasing element may advantageously be elastic. The atleast one biasing element may be elastic due to the shape thereof and/orthe material composition thereof. Advantageously, the at least onebiasing element may comprise or be made of plastic, in particularelastomer. Advantageously, the at least one biasing element may be orcomprise a spring element, in particular a leaf spring. The springelement may advantageously be made of an elastic metal.

The at least one biasing element may additionally have a sealingfunction. The at least one biasing element may be combined with a sealor a sealing unit, or vice versa. Additionally or alternatively, the atleast one biasing element may be realized with a non-return diaphragm ofthe treatment element, or vice versa. The non-return diaphragm makes itadvantageously possible to lock a passage for the fluid through thehousing, preferably the at least one inlet, in one direction of flow. Inthis manner, the fluid can be prevented from returning.

Optionally, a seal may be arranged between a pre-filtration side and apost-filtration side of the treatment element, in particular of a filterelement.

The at least one first connecting part and/or the at least one secondconnecting part may each be realized with a low material thickness incomparison to the radial and circumferential extension thereof withrespect to the connecting axis. The material thicknesses of the at leastone first connecting part and the at least one second connecting partmay be of similar size.

In another advantageous embodiment, the material thickness of the atleast one first connecting part and/or the at least one secondconnecting part may advantageously be at most 3 mm, preferably between 1and 2 mm.

In another advantageous embodiment, the axial extension of the at leastone insert gap may be at most 3 mm, preferably between 1 and 2 mm.

The connecting parts may be shaped—in particular, bent, folded, kinked,cut, punched, or the like—accordingly out of semi-finished products ormolded parts. The corresponding latch sections and (counter) guidingsections may optionally be realized in this manner.

Advantageously, at least a part of the semi-finished products or moldedparts may be provided radially inside the first connecting parts, whichare shaped—in particular, bent, folded, kinked, cut, punched, or thelike—out of semi-finished products or molded parts. Advantageously, thepart of the semi-finished products or the molded parts that is arrangedradially within the first connecting parts is closed in thecircumferential direction. This makes it possible to improve thestability of the connecting device and thus the rigidity and durabilityof the connection between the connecting devices.

The connecting parts may advantageously be arranged within the at leastone circumferential wall of the housing and/or the connecting head. Inthis manner, the bayonet-type connecting device is protected from thesurroundings. The connecting device may advantageously be arranged in acorresponding connection space between the housing and the connectinghead.

Advantageously, the at least one counter functional surface may abutagainst the corresponding functional surface over the largest possibleextension and preferably the entire extension thereof in thecircumferential direction as well as in the radial direction withrespect to the connecting axis. In this manner, the transmission offorces between the connecting parts can be improved. Corresponding guidecontours of the at least one counter functional surface may slide alongthe corresponding guide contours of the corresponding functional surfacewhen the connecting device is being opened or closed.

In this manner, it is possible to compress any biasing element and/or aseal when the connecting device is being closed. In the case of a seal,the sealing function can thus additionally be improved.

Advantageously, the at least one counter functional surface and thecorresponding functional surface interacting therewith may becomplementary. In this manner, said surfaces may lie flat against oneanother in the closed position of the connecting device. Thetransmission of forces can thus be improved. Loading of the componentsinvolved can thus be further reduced. The components may be dimensionedso as to be smaller in order to transmit equal forces. Adapting theshapes of the connecting parts to one another enables a correspondingreduction in the axial extensions of the connecting parts.Advantageously, the connecting parts may be mutually engaging moldedparts. The contours of the at least one counter functional surface andthe corresponding functional surface may slide along one another whenthe connecting device is being opened or closed.

In another advantageous embodiment, the at least one counter functionalsurface and at least the functional surface interacting therewith mayeach travel substantially helically about the connecting axis. In thismanner, the housing connecting part can be drawn toward the connectinghead in the axial direction at the same time as rotation of thetreatment element in the direction of closing, by means of theconnecting part. A combined rotational/plug-in movement can thus berealized. Advantageously, the pitches of the at least one counterfunctional surface and the at least one functional surface may beidentical.

Advantageously, the pitches may correspond to the pitch of a typicalright-handed thread. In this manner, the connecting device can be closedby rotation of the treatment element to the right and opened by rotationof the treatment element in the opposite direction, as is typical withfuel filters or oil filters.

Advantageously, a height may correspond axially to the connectingaxis—which is traveled when the bayonet-type connecting device isclosed—to an axial distance of a possible seal on the side of one of theconnecting parts from a corresponding seal surface on the side of theother connecting part. In this manner, the corresponding seal can bepositioned on the corresponding seal surface through therotational/plug-in connection when the connecting device is beingclosed.

In another advantageous embodiment, the treatment element—in particulara housing cover and/or an end plate of a possible filter element—and theconnecting head may each comprise at least one correspondence element,in particular a connecting piece, preferably a sealing connecting pieceand/or cylindrical connecting piece, which can correspond in a pairwisemanner when the treatment element is mounted. Advantageously,correspondence elements—in particular, the connecting pieces—may engagewith one another. In this manner, the correspondence elements may befixed radially with respect to the connecting axis relative to oneanother. Alternatively, the correspondence elements may be arranged inpairs abutting against, in particular with interposition of a sealingdevice. In this manner, radial positional tolerances can be easilycompensated with respect to the connecting axis.

Advantageously, at least one pair of correspondence elements mayradially outwardly and/or radially inwardly delimit a fluid-conductingspace.

In another advantageous embodiment, at least one pair of correspondenceelements may be arranged within at least one other pair ofcorrespondence elements. In this manner, a first fluid-conductingregion, in particular an outlet channel for the fluid, can be realizedin the inner pair of correspondence elements.

Between the inner pair of correspondence elements and the outer pair ofcorrespondence elements, there may advantageously be realized a secondfluid-conducting space, in particular an annular inlet space for thefluid.

The correspondence elements, in particular the pairs of correspondenceelements, may each be coaxial to the connecting axis. In this manner,the correspondence elements can be more easily positioned relative toone another. In addition, the fluid-conducting spaces may then becircumferentially more uniform.

At least one pair of correspondence elements, in particular a radiallyouter pair of correspondence elements, may advantageouslycircumferentially surround a plurality of fluid-conducting regions, inparticular at least one inlet region and at least one outlet region forthe fluid. In this manner, the corresponding fluid-conducting regionscan be easily delimited from the surroundings with only one pair ofcorrespondence elements. Here, contact regions between thecorrespondence elements of one pair may optionally be sealed off withonly one single sealing unit.

Advantageously, the connecting parts of the connecting device may bearranged radially outside of the pair of correspondence elements, whichmay circumferentially surround all of the fluid-conducting regions. Inthis manner, the fluid-conducting regions can be separated with only onepair of correspondence elements, optionally with only one sealingdevice, from the connecting parts of the connecting device andpreferably also from the surroundings. The connecting parts of theconnecting device can thus be easily protected from the fluid.

Advantageously, at least one sealing device, in particular a sealingring or preferably an O-ring seal or a combined seal/non-returndiaphragm may be arranged between the correspondence elements of atleast one pair. Thus, the fluid-conducting regions delimited with the atleast one pair of correspondence elements can be better sealed off fromthe contact region of the connecting pieces.

Advantageously, at least one fluid-conducting region of the treatmentdevice can be sealed off from the surroundings with the at least onesealing device. Advantageously, the outer sealing ring projects upwardsor downwards in the axial direction by at most 5 mm beyond theconnecting device. This is advantageous with respect to the use ofinstallation space because the sealing region uses the axial extensionof the connecting device.

Preferably, the at least one sealing device may surround the at leastone inlet and the at least one outlet circumferentially with respect tothe connecting axis. In this manner, with only one seal, it is possibleto seal a plurality, in particular all of the fluid-conducting spacesoff from the outside, in particular from the surroundings and/or fromthe connecting parts of the connecting device.

Advantageously, at least one sealing device, in particular a sealingring or a ring seal unit may be located as close as possible to theconnecting axis, and thus have the smallest possible diameter. In thismanner, it is possible to reduce a force which may be applied in theaxial direction to the connecting device by the at least one sealingdevice. The connecting parts of the connecting device can thus bemechanically relieved. Endowing the at least one sealing device with thesmallest possible diameter makes it possible to reduce the torquerequired to open or close the connecting device. Correspondingly, it isthen possible to reduce the required force of opening or closing. Thiscan have an advantageous impact on the ease of maintenance and/or thecapacity of the treatment element.

Advantageously, the at least one sealing device may comprise an O-ringor a molded seal. The sealing device may advantageously act so as toseal radially, in particular, outward or inward with respect to theconnecting axis. Additionally or alternatively, the at least one sealingdevice may act so as to seal in the axial direction.

The sealing groove of the sealing unit may be covered with a separatecover ring on the side thereof that faces axially away from the filterbellows. The cover ring may then be connected to the outer sealingconnecting piece by means of clamping lugs.

In a preferred embodiment, the sealing groove of the sealing unit is notformed by means of a separate cover ring, but rather as part of thehousing cover, integrally with the housing cover. This can have anadvantageous impact on the capacity of the treatment element.

Advantageously, at least one sealing device may be arranged on thetreatment element, in particular on the housing cover and/or optionallythe end plate of the filter element. In this manner, the at least onesealing device can be replaced together with the treatment element.

Advantageously, at least one spacer may be provided between thetreatment element, in particular the end plate of the filter element.The spacer may be a plastic spacer. Connected to this is the advantageof a greater ease of manufacturing.

Advantageously, the at least one guiding element may brush along thecorresponding at least one functional surface when the treatment elementis rotated. In this manner, in particular when the connecting device isopened, an axial pressing-off force on the corresponding functionalsurface can be generated. With the axial pressing-off force, it ispossible to press against a mechanical holding force of the at least onesealing device. Thus, the at least one sealing device can be withdrawnor rotated from a corresponding sealing surface, or vice versa.

In another advantageous embodiment, a material thickness of the at leastone first connecting part and/or the at least one second connecting partin the circumferential direction may be respectively constant in theregion of the at least one functional surface/counter functionalsurface. The space required for the connecting device—in particular, theaxial space—can thus be reduced.

In another advantageous embodiment, the at least one first connectingpart and/or the at least one second connecting part may be made of sheetmetal or comprise sheet metal. Sheet metal can generally be present inthe initial state, as rolled metal in the shape of flat, level panels orstrips. Sheet metal is easily realized with a uniform thickness. Amechanically stable connecting part can also be realized with arelatively small material thickness from sheet metal. In this manner,the required installation space, in particular in the axial direction,for the connecting device can be reduced. Sheet metal can be easilymachined or processed, in particular bent, folded, punched, cut, orwelded. With sheet metal, it is easy to realize connections betweencomponents, in particular crimped connections or welded connections.Advantageously, at least one of the connecting parts may be implementedas a shaped sheet metal part.

Advantageously, at least one of the connecting parts may be fixedly orreleasably connected to the treatment element. At least one of theconnecting parts may be fixed or releasably connected to the connectinghead. The at least one connecting part may be connected to the treatmentelement or the connecting head by means of a materially integralconnection and/or a positive and/or non-positive connection, inparticular by means of a crimped connection, a welded connection, aclamped connection, a latched connection, a plug connection, a threadedconnection, and/or an adhesive connection.

Advantageously, the housing connecting part may be connected to thehousing cover and/or the housing pot, in particular by means of acrimped connection and/or a welded connection. In this manner, thehousing connecting part may be stably connected to the treatmentelement. The housing connecting part may then be easily replacedtogether therewith.

Advantageously, the housing connecting part may be held on the housingby means of a crimped connection formed between the housing cover andthe housing pot.

The housing connecting part may advantageously be flush in the axialdirection with the axially outermost surface of the crimped connectionprovided between the housing cover and the housing pot.

Advantageously, the housing cover may be connected in a sealed manner tothe housing pot with the use of a sealing material, in particular asealant, by means of a crimped connection

Advantageously, a head-side connecting part may preferably be threadedor welded onto the connecting head. The use of a threaded connectionmakes it possible for the head-side connecting part to be easilyreleased from the connecting head when necessary.

Advantageously, the housing cover may be, in particular, elasticallydeformable. The housing cover can then be pressed against the connectinghead by an overpressure, in particular, one that prevails in the housingduring operation of the treatment device. The connecting head can thussupport the housing cover. It is thus possible to reduce therequirements for the pressure stability of the housing cover. Thehousing cover can then be more easily realized, in particular fromsimpler materials.

Advantageously, a plurality of functional surfaces of the at least onefirst connecting part and corresponding counter functional surfaces ofthe at least one second connecting part may be arranged so as to becircumferentially, in particular, uniformly distributed with respect tothe connecting axis. It is thus possible to improve a circumferential,in particular uniform transmission of force. It is additionally possibleto reduce overall an angle of rotation that is required to close andopen the connecting device. The circumferential extension of each of theindividual functional surfaces/counter functional surfaces may be thenbe lower than with the use of only one single pair of one counterfunctional surface and one corresponding functional surface. Achieving acomparable uniform transmission of force requires that a single pair ofone counter functional surface and one functional surface extend atleast once over the entire circumference.

Advantageously, the treatment device may be a filter device forfiltering liquid fluids, in particular fuel, oil, or water. The filterdevice may advantageously be used in an internal combustion engine.

Advantageously, the treatment element may be a replaceable filter, inparticular a replaceable filter for oil or fuel. The housing of thetreatment element may then be a filter housing. Advantageously, in thefilter housing, at least one filter element may be arranged so as to beable to separate the at least one inlet from the at least one outlet.The connecting head may advantageously be a filter head, onto which thereplaceable filter, in particular the filter housing can be releasablymounted by means of the connecting device.

A replaceable filter is typically a filter with which the at least onefilter element is replaced together with the filter housing. Generally,the at least one filter element is arranged fixedly in the filterhousing. Correspondingly, the connections between the housing pot andthe housing cover need not be non-destructively releasable.

The invention is not limited to a treatment device of an internalcombustion engine of a motor vehicle. Rather, the invention may also beused for other types of internal combustion engines, in particularindustrial engines. The invention can also be used with other types oftreatment devices for fluid inside or outside the field of motor vehicletechnology. The invention may even be used with air de-oiling boxes ordesiccant boxes.

This problem is also solved through the treatment element in that: thetreatment element comprises at least one first one of the connectingparts and/or at least one second one of the connecting parts, whereinthe at least one first connecting part has a respective functionalsurface on faces lying axially opposite one another with respect to theconnecting axis; at least one second connecting part of the connectingparts has at least one counter functional surface which engages behindone of the functional surfaces of the at least one first connecting partfor interaction purposes; at least one guiding element is arranged onthe face of the at least one second connecting part, said guidingelement delimiting at least one insert gap together with the at leastone counter functional surface, the axial extension of the insert gapwith respect to the connecting axis being at least as large as themaximum axial distance between the two axially opposing functionalsurfaces of the at least one first connecting part; and the at least onefirst connecting part can be guided in the insert gap when theconnecting device is being opened/closed, one of the functional surfacesof the at least one first connecting part being guided along the counterfunctional surface, and the other functional surface being guided alongthe at least one guiding element.

The advantages and features shown in connection with the treatmentdevice according the invention and the advantageous embodiments thereofapply correspondingly to the treatment element according to theinvention and the advantageous embodiments thereof, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages, features, and details of the invention shall be mademore apparent by the following description, which addresses embodimentsof the invention in greater detail, with reference to the accompanyingdrawings. The features disclosed in the drawings, the description, andthe claims in combination will be individually considered, asappropriate, and combined into other appropriate combinations by aperson skilled in the art. In the schematic drawings,

FIG. 1 illustrates a longitudinal section of a filter device for engineoil of an internal combustion engine of a motor vehicle along a cut lineI-I from FIG. 3, with a filter head and a replaceable filter that isconnected to the filter head by means of a releasable bayonet-typeconnecting device;

FIG. 2 illustrates a longitudinal section of the filter device from FIG.1 along a cut line II-II from FIG. 3;

FIG. 3 is a plan view of the filter device from FIGS. 1 and 2;

FIG. 4 is a detail view of the longitudinal section of the filter devicefrom FIG. 1, in the region of the connecting device;

FIG. 5 is an isometric depiction of the replaceable filter of the filterdevice from FIGS. 1 to 4;

FIG. 6 is an isometric depiction of the filter head of the filter devicefrom FIGS. 1 to 4; and

FIG. 7 illustrates a longitudinal view of a filter device according to asecond embodiment, similar to the filter device from FIGS. 1 to 6.

In the drawings, like components are assigned like reference signs.

DETAILED DESCRIPTION

FIGS. 1 to 6 illustrate different perspectives, sections, and detailviews of a filter device 10 for engine oil of an engine oil circuit ofan internal combustion engine of a motor vehicle, and componentsthereof. The filter device 10 serves to purify the engine oil.

The filter device 10 comprises a filter head 12, to which a replaceablefilter 14 is releasably attached. The filter head 12 is fixedlyconnected to the internal combustion engine and serves as a connectorpart for the replaceable filter 14. FIG. 6 illustrates the filter head12 in detail. The filter head 12 comprises a feed 16 and a discharge 18for the engine oil. The feed 16 and the discharge 18 are connected tocorresponding oil lines of the internal combustion engine, in a mannerthat is not of further interest here.

The filter head 12 further comprises a radially inner connecting piece22 that is coaxial with respect to a connecting axis 20.

Subsequent discussion of “axial,” “radial,” “coaxial,”“circumferential,” or the like is made with respect to the connectingaxis 20, unless otherwise indicated. In the embodiment depicted, theconnecting axis 20 coincides with a filter axis of the replaceablefilter 14.

The inner connecting piece 22 is approximately circularly cylindrical.The connecting piece extends on the side of the filter head 12 thatfaces the replaceable filter 14. It is open on both end faces. On theside thereof that faces away from the replaceable filter 14, the innerconnecting piece 22 is connected fluidically to the discharge 18.

The inner connecting piece 22 is surrounded coaxially by a circularlycylindrical, radially outer connecting piece 24. The inner connectingpiece 22 projects beyond the outer connecting piece 24 in the axialdirection on the side thereof that faces the replaceable filter 14.

The inner connecting piece 22 and the outer connecting piece 22 eachcircumferentially delimit a coaxial annular inlet space 26. The annularinlet space 26 is connected to the feed 16 via a fluid connection.

The inner connecting piece 22 and the outer connecting piece 24 arecoaxially surrounded by a circularly cylindrical circumferential wall28. The free edge of the circumferential wall 28 facing the replaceablefilter 14 is located approximately at the same axial height as the freeedge of the outer connecting piece 24. The circumferential wall 28 formsthe radially outer delimitation of the filter head 12 on the side facingthe replaceable filter 14. The circumferential wall 28 and the outerconnecting piece 24 each circumferentially delimit an annular, coaxialconnection space 30.

Arranged in the connection space 30 is a head connecting part 32 of areleasable bayonet-type connecting device 34. The replaceable filter 14is releasably attached with the connecting device 34 to the filter head12. The head connecting part 32, which overall is approximately annularin shape, is formed of sheet metal. The thickness of the sheet metal isconstant, at about 2 to 3 mm.

Radially inwardly, the head connecting part 32 comprises an annular headmounting section 36. The head mounting section 36 pushes with theradially inner circumference side thereof approximately against theradially outer circumference side of the outer connecting piece 24. Thehead mounting section 36 extends radially and circumferentiallyapproximately in the same plane. The head connecting part 32 extendsradially approximately as far as the middle of the connection space 30.

The head mounting section 36 passes into four head-side bayonet sections38. The head-side bayonet sections 38 are identical in shape and size.The head-side bayonet sections 38 are arranged so as to be distributedcircumferentially uniformly. The head-side bayonet sections 38 each havea circumference section 40 that extends substantially circumferentiallyparallel to an imaginary circular cylinder connecting part about theconnecting axis 20. The circumference sections 40 each pass into afunctional section 42 on the sides thereof facing away from the headmounting section 36. The circumference sections 40 thus connect the headmounting section 36 to the respective portion sections 42. Thefunctional sections 42 are easily visible in particular in FIG. 6. Thefunctional sections 42 each have a counter functional surface 44 on theside thereof facing away from the replaceable filter 14.

The functional sections 42, in particular the counter functionalsurfaces 44, each travel approximately helically about the connectingaxis 20. The pitch of the counter functional surfaces 44 and thefunctional sections 42 corresponds approximately to the pitch of atypical right-handed thread. Viewed axially out from the replaceablefilter 14, the ends of the functional sections 42 that are to the frontin the clockwise direction are each closer to the replaceable filter 14than the ends that are to the rear in the clockwise direction. Presentbetween the front ends of the functional sections 42 and the place ofthe head mounting section 36 are respective gaps through whichcorresponding housing-side bayonet sections 104 (described in greaterdetail below) can be introduced.

The sheet metal of the head connecting part 32 is of equal thickness inthe head mounting section 36, in the circumference sections 40, and inthe functional sections 42. This also signifies that the sheet metal hasa uniform axial extension in the head mounting section 36 and in thefunctional sections 42.

The functional sections 42 each have a head-side latching projection 46.The latching projections 46 are realized as respective bends in thecounter functional surfaces 44. The latching projects 46 rise axially onthe side facing the replaceable filter 14.

Viewed out from the replaceable filter 14, a guide peg 48 is arranged infront of each of the functional sections 42 in the clockwise direction.The guide pegs 48 are illustrated, for example, in FIG. 6. The guidepegs 48 are attached to the filter head 12 in a manner separated fromthe head connecting part 32. The guide pegs 48 are each located at theinsertion side of the head-side bayonet sections 38. With the counterfunctional surfaces 44, the guide pegs there each delimit a head-sideinsert gap 50, also illustrated in FIG. 6.

The head connecting part 32 is attached to the filter head 12 at thehead mounting section 36 with four screws 52 in total, as illustrated inFIG. 6, from the side facing the replaceable filter 14. The screws 52are each located between an end of one of the head-side bayonet sections38 to the rear in the clockwise direction and one of the guide pegs 48in front of the end of the next head-side bayonet section 38 to thefront in the clockwise direction.

An annular leaf spring 54 is also arranged coaxially in the connectionspace 30. A radially outer circumferential side of the leaf spring 54extends circumferentially along the radially inner circumferential sideof the circumferential wall 28. The leaf spring 54 has four spring armsin total. The spring arms are distributed circumferentially uniformly.With respect to the connecting axis 22, the spring arms extendapproximately helically in the same direction of rotation as thefunctional sections 42 of the head connecting part 32. The spring armsare resiliently flexible in the axial direction.

The replaceable filter 14 is designed as a spin-on filter having acircular cross-section. The replaceable filter is substantially coaxialto the connecting axis 20. The replaceable filter 14 comprises a filterhousing 56 having a housing pot 58, to open sides of which a housingcover 60 is attached at the radially outer edge thereof by means of acrimped connection. A radially outer diameter of the filter housing 56in the region of the housing cover 60 is smaller than a radially innerdiameter of the circumferential wall 28 of the filter head 12. Thehousing pot 56 has an outwardly curved housing bottom 62. The housingcover 60 and the housing pot 58 are made of metal.

A coaxial filter element 64 is arranged in the housing pot 58. Thefilter element 64 has a filter medium that is folded into a filterbellows 66 and is circumferentially closed. At end faces thereof, thefilter bellows 66 is respectively connected in a sealed manner to aconnecting end plate 68 (above in FIG. 1) and a counter end plate 70(below in FIG. 1). The connecting end plate 68 is located on the side ofthe filter element 64 that faces the housing cover 60.

The filter bellows 66 surrounds an element interior space 72 of thefilter element 64. The element interior space 72 is located on apost-filtration side of the filter element 64.

The counter end plate 70 closes the element interior space 72 on the endface of the filter element 64 that faces the housing bottom 62.Supported on the outer side of the counter end plate 70 that faces thehousing bottom 62 are a plurality of spring elements 74, which in turnare supported on the housing body 62 on the other side.

A spring-loaded bypass valve 76 is arranged in the counter end plate 70,the bypass valve allowing an oil flow of engine oil from the housingbottom 62 directly into the element interior space 72, bypassing thefilter medium, in the opened state (under conditions not of furtherinterest here). The bypass valve 76 is depicted in the closed positionin FIG. 1.

The filter element 64 is surrounded radially outwardly by apre-filtration-side annular space 78 that is delimited by the radiallyinner circumferential side of the housing pot 58.

A coaxial central tube 80 also extends in the element interior space 72,between the counter end plate 70 and the connecting end plate 68. Acircumferential wall of the central tube 80 is permeable to the engineoil. A radially inner circumference side, namely, radially inner pleatedges of the filter bellows 66 can be supported on the radially outercircumference side of the central tube 80.

The connecting end plate 68 has a coaxial outlet opening 82 for thefiltered engine oil. The connecting end plate 68 is molded on theradially inner circumferential side into a coaxial cylindricalconnecting piece 83 that extends axially away from the element interiorspace 72.

An annular coaxial inner sealing unit 84 is attached to the side facingaxially way from the element interior space 72. The inner sealing unit84 is composed of an elastomer.

Radially outwardly, the inner sealing unit 84 has a non-return diaphragm86. The non-return diaphragm 86 is annular in shape and surrounds thecylindrical connecting piece 83 radially outwardly. The non-returndiaphragm 86 abuts against the inner side of the housing cover 60 thatit faces the filter bellows 66, under a mechanical bias. The non-returndiaphragm, as illustrated in FIGS. 1, 2, and 4, closes off a coaxialannular inlet opening 88 of the housing cover 60 for engine oil, in thepressure-free state. As soon as engine oil is supplied to the filterdevice 10, the non-return diaphragm 86 opens in the direction of passagethrough, due to the oil pressure. The non-return diaphragm 86 preventsthe engine oil from returning through the inlet opening 88.

A radially inner ring section of the inner sealing unit 84 forms acoaxial inner sealing ring 90. The inner sealing ring 90 abuts in asealed manner at the radially outer circumference side thereof againstthe radially inner circumference side of the cylindrical connectingpiece 83. The inner sealing ring 90 abuts in a sealed manner at theradially inner circumference side thereof—when the replaceable filter 14has been mounted—against a radial outer circumference side, designed tobe a sealing surface, of the radially inner connecting piece 22. Withthe inner sealing ring 90, the post-filtration side of the replaceablefilter 14 is separated from the pre-filtration side thereof in theregion of the inlet opening 88.

The housing cover 60 comprises a stepped coaxial outer sealingconnecting piece 92 in the region of the inlet opening 88. A narrowingof the outer sealing connecting piece 92 at the end thereof that facesaxially away from the filter bellows 66 forms an outer sealing groove 94for an outer sealing ring 96. The outer sealing ring 96 is designed asan O-ring.

A radially outer diameter of the outer sealing connecting piece 92outside of the region of the sealing groove 94 corresponds approximatelyto the radially inner diameter of the outer connecting piece 24 of thefilter head 12. When the replaceable filter 14 is mounted, the sealingconnecting piece 92 is inserted into the outer connecting piece 24.

The radially outer circumference side of the outer sealing connectingpiece 92 abuts then against the radially inner circumference side of theradially outer connecting piece 24.

The outer sealing groove 94 is covered with a cover ring 98 on the sidethereof that faces axially away from the filter bellows 66. The coverring 98 is connected to the outer sealing connecting piece 92 by meansof four clamping lugs.

When the replaceable filter 14 is mounted, the outer sealing ring 96abuts against the radial inner circumference side, designed as a sealingsurface, of the radially outer connecting piece 24 in a sealed manner.The outer sealing ring 96 thus separates the oil-conducting region ofthe filter device 10 from the connection space 30 and from thesurroundings.

An annular coaxial housing connecting part 100 of the connecting device34 is molded out of sheet metal. A thickness of the sheet metal of thehousing connecting part 100 corresponds approximately to the thicknessof the sheet metal of the head connecting part 31.

The housing connecting part 100 extends radially from the radially outercircumference side of the housing cover 60 to over the radial center ofthe connection space 30. The housing connecting part 100 overlaps withthe head connecting part 32.

The housing connecting part 100 comprises a housing mounting section 102that extends radially and circumferentially approximately in the sameplane. The housing mounting section 102 is fixed radially outwardlybetween the housing cover 60 and the crimped connection of the housingpot 58 to the housing cover 60. The housing mounting section rests onone side flat against the housing cover 60.

The housing mounting section 102 passes on the radially inner sidethereof into four identical housing-side bayonet sections 104. Thehousing-side bayonet sections 104 are arranged so as to be distributedcircumferentially uniformly. The housing-side bayonet sections haveapproximately the same shape and size as the head-side bayonet sections38.

The housing-side bayonet sections 104 have, on axially opposite sides,an inner functional surface 106 and an outer functional surface 108. Thefunctional surfaces 106 and 108 extend opposite to the counterfunctional surfaces 44, each approximately helically about theconnecting axis 20, with the same pitch as the counter functionalsurfaces 44.

The inner functional surfaces 106 are located on the side of therespective housing-side bayonet section 104 that faces the housing cover60. The outer functional surfaces 108 are correspondingly located on theaxially opposite side. In the closed state of the connecting device 34,the outer functional surfaces 108 each are engaged from behind by one ofthe counter functional surfaces 44 of one of the head-side bayonetsections 38, for the purpose of interaction. Then, the outer functionalsurfaces 108 each abut flat against the corresponding counter functionalsurfaces 44.

The housing-side bayonet sections 104 each comprise a housing-sidelatching projection 110. The latching projections 110 rise axially awayfrom the housing cover 60. When the replaceable filter 14 is mounted,the housing-side latching projections 110 lock behind the correspondinghead-side latching projections 46.

For the purpose of installation, the replaceable filter 14 is insertedforward, with the housing cover 60, coaxially onto the connection sideof the filter head 12.

At the latest when the cover ring 98 arrives at the end face of theradially outer connecting piece 24 of the filter head 12 and/or thehousing connecting part 100 arrives at the head connecting part 32, thereplaceable filter 14 is additionally rotated about the connecting axis20 in the right-handed direction of rotation, which is the direction ofrotation for closing the connecting device 34.

As soon as the free ends of the housing-side bayonet sections 104 arepositioned in the region of the corresponding head-side insert gaps 50,the respective outer functional surfaces 108 begin to be guided alongthe corresponding counter functional surfaces 44 on the respective guidepegs 48 and the inner functional surfaces 106. The spring arms of theleaf springs 54 are supported with the free ends thereof on the housingconnecting part 100 in the axial direction. The tension achieved by thehelical pitch of the counter functional surfaces 44 and the innerfunctional surfaces 106 in the axial direction between the bayonetsections 38 and 104 draws the inner sealing ring 90 onto the radiallyinner connecting piece 22 and the outer sealing ring 96 into theradially outer connecting piece 24.

As soon as the housing-side latching projections 110 abut against thecorresponding head-side latching projections 46, a corresponding lockingforce must be overcome in order to continue turning. The locking forceis realized through the restoring force of the spring arms of the leafspring 54.

After the locking force is overcome, the housing-side latchingprojections 110 lock behind the housing-side latching projections 46,and thus ensure against an unintentional opening of the connectingdevice 34.

In order to separate the replaceable filter 14 from the filter head 12,the replaceable filter 14 is rotated to the left, i.e., the direction ofopening rotation, about the connecting axis 20. This requires firstovercoming the locking force of the housing-side latching projections110 with the head-side latching projections 46.

Under the spring biasing of the leaf spring 54, the inner functionalsurfaces 106 are guided along the corresponding counter functionalsurfaces 44. In addition, the outer functional surfaces 108 are guidedalong the respective guide pegs 48. Then, with the guide pegs 48, arespective axial pressing-off force onto the outer functional surfaces108 is generated, and acts against a respective holding force of theinner sealing ring 90 and the outer sealing ring 96. The holding forcesare realized through the respective friction between the inner sealingring 90 and the inner connecting piece 22, and between the outer sealingring 96 and the outer connecting piece 24. The pressing-off force drawsthe inner sealing ring 90 off in the axial direction from the innerconnecting piece 22, and draws the outer sealing ring 96 out from theouter connecting piece 24.

As soon as the housing-side bayonet sections 104 leave the correspondinghead-side insert gaps 50 after further rotational movement, thereplaceable filter 14 is drawn away from the filter head 12 with anaxial movement.

When the filter device 10 is operating, i.e., when the internalcombustion engine is operating, engine oil to be purified flows throughthe feed 16, indicated by an arrow 112, into the annular inlet space 26.The engine oil flows out from there through the inlet opening 88, and isreleased by the non-return diaphragm 86 into the pre-filtration-sideannular space 78 of the filter housing 56. The engine oil to be purifiedflows through the filter bellows 66 from radially outward to radiallyinward, and passes through the openings of the central tube 88 into theelement interior space 72. From the element interior space 72, thepurified engine oil passes through the outlet opening 82 and theradially inner connecting piece 22 of the filter head 12 to thedischarge 18. The purified engine oil leaves the filter head 12 andtherewith leaves the filter device 10, through the discharge 18.

FIG. 7 illustrates a second embodiment of a filter device 10. Thoseelements that are similar to those of the first embodiment from FIGS. 1to 6 are provided with the same reference signs. The second embodimentdiffers from the first embodiment in that an inner seal 190 of the innersealing unit 84 is arranged in an axially sealing manner between theradially inner connecting piece 22 of the filter head 12 and thecylindrical connecting piece 83 of the replaceable filter 14. Theconnecting piece 22 and the cylindrical connecting piece 83 have thesame diameter. The connecting piece and the cylindrical connecting pieceabut against one another in the axial direction of the interposition ofthe inner seal 190.

An outer sealing ring 196 is located radially outward between a radiallyinner circumference side of a coaxial cylindrical section of the housingcover 60 and a radially outer circumference side of the circumferentialwall 28 of the filter head 12. The outer sealing ring 196 seals theconnection space 30 off from the surroundings. The connection space 30itself is fluidically connected to the annular inlet space 26.

In addition, the second embodiment forgoes a bypass valve.

1. A treatment device (10) for filtering fluids comprising: a treatmentelement (14); a housing (56) comprising a housing pot (58); a housingcover (60); at least one inlet (88) for the fluid to be treated; and atleast one outlet (82) for the treated fluid; a connecting head (12)having at least one feed (16) for the fluid to be treated, said feedbeing connectable to the at least one inlet (88), and/or at least onedischarge (18) for the treated fluid, said discharge being connectableto the at least one outlet (82); wherein the connecting head (12) andthe treatment element (14) are connected to each other by means of areleasable bayonet-type connecting device (34) through the execution ofa rotational/plug-in movement about a connecting axis (20) of thetreatment device (10); and wherein the connecting device (34) has atleast one housing connecting part (100) on the side of the housing (56);and at least one head connecting part (32) on the side of the connectinghead (12); wherein said connecting parts interact with each other inorder to connect the connecting device (34); wherein at least one firstconnecting part (100) has a functional surface (106, 108) on respectivesides lying axially opposite to one another with respect to theconnecting axis (20); wherein at least one second connecting part (32)has at least one counter functional surface (44) that engages one of thefunctional surfaces (106) of the at least one first connecting part(100) from behind, for interaction purposes; wherein the materialthickness of the connecting part (100) is constant at least in theregion of the at least one functional surface (106, 108).
 2. Thetreatment device (10) according to claim 1, wherein the outer sealingring (96) projects upward by up to 5 mm in the axial direction beyond anuppermost point of the housing connecting part (100) in the axialdirection, and projects downward by up to 5 mm in the axial directionbeyond a lowermost point of the housing connecting part (100) in theaxial direction.
 3. The treatment device (10) according to claim 1,wherein the outer sealing ring (96) is arranged radially within thehousing connecting part (100).
 4. The treatment device (10) according toclaim 1, wherein on the side of the at least one second connecting part(32), at least one guiding element (48) is arranged, which delimits atleast one insert gap (50) with the at least one counter functionalsurface (44), an axial extension of the insert gap with respect to theconnecting axis (20) being at least as large as the maximum axialdistance of the two axially opposite functional surfaces (106, 108) ofthe at least one first connecting part (100), and the at least one firstconnecting part (100) is guided in the insert gap when the connectingdevice (34) is being opened/closed; wherein one of the functionalsurfaces (106) of the at least one first connecting part (100) is guidedalong the counter functional surface (44) and the other of thefunctional surfaces (108) is guided along the at least one guidingelement (48).\
 5. The treatment device according to claim 1, wherein theat least one counter functional surface (44) and the at least onefunctional surface (106) interacting therewith each comprise at leastone latch element (46, 110) as a latching projection or a latch sectionof at least one catch lock, which latch one behind the other or with orinto one another in the closed position of the at least one connectingdevice (34).
 6. The treatment device according to claim 1, wherein theconnecting device (34) comprises at least one biasing element (54; 190)for realizing a mechanical biasing with which the at least one counterfunctional surface (44) is pressed against the at least one functionalsurface (106).
 7. The treatment device according to claim 1, wherein amaterial thickness of the at least one first connecting part (32) and/orthe at least one second connecting part (100) is at most 3 mm.
 8. Thetreatment device according to claim 1, wherein an axial extension of theat least one insert gap (50) is at most 3 mm.
 9. The treatment deviceaccording to claim 1, wherein the at least one counter functionalsurface (44) and at least the functional surface (106) interactingtherewith each travel approximately helically about the connecting axis(20).
 10. The treatment device according to claim 1, wherein the housingcover (60) and/or an end plate (68) of a filter element (64) and theconnecting head (12) each comprise at least one correspondence elementas a sealing connecting piece (92) and/or cylindrical connecting piece(83), which correspond in a pairwise manner when the treatment element(14) is mounted.
 11. The treatment device according to claim 10, whereinat least one pair of correspondence elements (22, 83) is arranged withinat least one other pair of correspondence elements (24, 92).
 12. Thetreatment device according to claim 1, wherein the at least one firstconnecting part (32) and/or the at least one second connecting part(100) is/are made out of sheet metal or comprise(s) sheet metal.
 13. Atreatment element (14) of a treatment device for treating and/orfiltering fluids, comprising: a housing (56) comprising a housing pot(58); a housing cover (60); at least one inlet (88) for the fluid to betreated; and at least one outlet (82) for the treated fluid; wherein thetreatment element (14) is configured and adapted to connect to aconnecting head (12) of the treatment device (10) by means of areleasable bayonet-type connecting device (34) through the execution ofa rotational/plug-in movement about a connecting axis (20) of thetreatment device (10); and the connecting device (34) has at least onehousing connecting part (100) on the side of the housing (56) that caninteract with at least one head connecting part (32) on the side of theconnecting head (12) for the purpose of connecting the connecting device(34); wherein the at least one inlet (88) can be connected to at leastone feed (16) of the connecting head (12) for the fluid to be treatedand/or the at least one outlet (82) can be connected to at least onedischarge (18) of the connecting head (12) for the treated fluid;wherein the treatment element (14) comprises at least one connectingpart (100), wherein the at least one connecting part (100) comprisesrespective functional surfaces (106, 108) on sides lying axiallyopposite to one another with respect to the central axis (20), whereinthe material thickness of the at least one connecting part (100) isconstant at least in the region of the at least one functional surface(106, 108).
 14. The treatment element (14) according to claim 13,wherein the connecting part (100) is attached to the housing by means ofa crimped connection between the housing cover and the housing pot. 15.The treatment element (14) according to claim 13, wherein the connectingpart (100) is attached to the housing by means of a materially integralconnection to the housing cover and/or to the housing pot.
 16. Thetreatment element (14) according to claim 13, wherein the housing cover(60) comprises sheet metal.
 17. The treatment element (14) according toclaim 13, wherein the material thickness of the housing cover (60) is0.4 to 1 mm.
 18. The treatment element (14) according to claim 13,wherein the outer sealing ring (96) projects upward by up to 5 mm in theaxial direction beyond an uppermost point of the housing connecting part(100) in the axial direction, and projects downward by up to 5 mm in theaxial direction beyond a lowermost point of the housing connecting part(100) in the axial direction.
 19. The treatment element (14) accordingto claim 13, wherein the outer sealing ring (96) is arranged radiallywithin the housing connecting part.
 20. The treatment element (14)according to claim 13, wherein the at least one connecting part (32) ismade of sheet metal or comprises sheet metal.
 21. The treatment element(14) according to claim 13, wherein the material thickness of the atleast one connecting part (100) is at most 3 mm.
 22. The treatmentelement (14) according to claim 13, wherein the at least one functionalsurface (106) respectively comprises at least one latch element (110) asa latching projection or a latch section, of at least one catch lock.23. The treatment element (14) according to claim 13, wherein the atleast one functional surface (106) respectively travels approximatelyhelically about the connecting axis (20).